Wireless-controlled aerial torpedo



WIRELESS CONTROLLED AERIAL TORPEDO Original Filed Dec. 18 1917 8 Sheets-Sheet 1 lllllllllh IN VE N TOR Feb. 17, 1931. E. A. SPERRY 1,792,937

WIRELESS CONTROLLED AERIAL TORPEDO Original Filed Dec. 18, 1917 8 Sheets-Sheet 2 iiiiiiiiiiiliiii ili lllllllllllllllll III III/MI,

20 20 Q a o 0 G u o ,MU W

ATTOR EY Feb; 17, 1931. E. A. SPE'RRY 1,192,937

WIRELESS CONTROLLED AERIAL TORPEDO Original Filed Dec. 18, 1917 3 Sheets-Sheet a INVENTOI? Feb. 17, 1931. E. A. SPERRY 1,792,937

I v WIRELESS CONTROLLED AERIAL TORPEDO Original Filed Dec. 18 1917 8 Sheets-Sheet 4 25o 24r- W 45.

HIM-v 6 2?? 8/ 2 27/ I278 264 HI 0 6 QJ' IIIH' 272- 1 79 @WW 1! 275 Q I! 11. w

INVENTOR HMER/ZEPERRY.

Feb. 17, 1931. SPERRY 1,792,937

WIRELESS CONTROLLED AERIAL TORPEDO Original Filed Dec. 18, 1917 8 Sheets-Sheet 5 lllllllllHll l l/VVE/V TOR L7MR5ZSPRRX Feb. 17, 1931. .E. A. SPERRY 37 WIRELESS CONTROLLED AERIAL TORPEDO Original Filed 1917 a Sheets-Sheet e 30K 5a mummllljm 4 Feb. 17, 1931. SPERRY 1,792,937

WIRELESS CONTROLLED AERIAL TORPEDd Original Filed Dec. 18, 19l7 8 Sheets-Sheet 8 INVENTOR 5M5; 55 mm? Patented Feb. 11, 1931 EIMER a SPERRY,

PATENT OFFICE OF BROOKLYN, NEW YORK, ASSIGNQR TO THE SPERRY eYnosoorn COMPANY mm, A CORPORATION OF EW YORK WIRELESS-CONTROLIED AEBIAL TORPEDO Application filed December 18, .1917. SeriaLNo. 207,786. Renewed February 23, 1928.

This invention relates to aerial torpedoes, more specifically to an aerial torpedo adapted to be controlled, when in flight, from the ground or from an aircraft other than the.

one carrying the explosive charge or charges.

One of the'principal objects of the present invention is to provide a system of control whereby the direction of flight of the aerial torpedo may be controlled from the home or sending station throughout the entire flight.

Another important object is to provide .means whereby the above mentioned manual sion of the explosive or explosives carried by p the aerial device while adjacent the home station and to provide means for preventing control of the device from any source other than the home or sending station. Other objects and advanta eswill appear as the invention is hereina ter developed.

Referring to the drawings which illustrate what I now consider the preferred form of my invention:

Fig. 1 is an elevational view of an aircraft with my invention applied thereto.

Fig. 2 is a fragmentary detail elevation,-

partly in section and illustrating a torpedo adapted to be releasably carried by my device.

Fig. 3 is a preferred form of wiring diagram of the apparatus located at the home or sending station.

Fig. 4 is an inverted plan view, with the casing removed, of one form of sending means or automatic key.

Fig. 5 is a vertical section on the line 5-5 of Fig. 4.

Fig. 6 is a shown in Figs. 4 and 5.

Figs. 7 and 8 are fragmentary details of top planview of the structure D certain of the parts shown'in Figs. 4 and 6.

Fig. 9 is a plan view of one form of. selectivemeans used on the aerial torpedo.

Fig. 10 is an end elevation of the apparatus shown in Fig. 9 with the end plate removed.

Fig. 11 is an elevation of the apparatus being omitted.-

shown in Fig. 9, the parts shown in Fig. 10

Fig. 12 is a fragmentary detail elevation of the mechanism shown in Fig. 10 with th members 69, 82 and 64 removed.

Fig. 13 is a plan view of one form of stabilizing and steering control mechanism adapted to be carried by the aerial device.

Figs. 14 and 15 are detail elevations of the control gyros forming a part of the mechanism illustrated in Fig. 13.

Fig. 16 is a fragmentary detail elevation of certain of the parts illustrated in Fig. 14. Fig; 17 is a detail elevation illustrating one form of gearing employed in connection with the servo-motors forming a part of the mechanism shown in Fig. 13.

Figs. 18 and 19 are respectively a detail lan and elevation of one form of distance controlled mechanism employed in my system.

Fig. 20 is an enlarged plan view of the relay mechanism forming a part of the ap paratus shown in Fig. 13.

Fig. 21 is a sectional elevation taken on the line 21-21 of Fig. 20.

Fig. 22 is a fragmentary detail of a part of the mechanism shown in Fig. 20.

Fig. 23 is a diagrammatic view illustrating the relationship between certain of the parts shown in Figs. 20 and 21.

Fig. 24 is a wiring diagram of the mechanism located on the aerial device.

Fig. 24a is a partly diagrammatic view illustrating certain additional features which maybe embodied in my system.

Fig. 25 is a fragmentary detail of certain parts shown in Fig. 13.

In the form of my invention herein disclosedv I utilize among other instrumentalities mechanism at the home or control station, .which I term sending means,

' and selective. means. While these means oppositely might assume various forms I find that the system and'apparatus invented by'Thomas H- Phillips, Jr., Patent No. 1,525,431 dated February 3, 1925, is well adapted for use in my combination, and I have accordingly illustrated that system.

The sending means comprises a manually operable circuit controller and an automaticall operable one. The automatic controller is s shaft 1 suitably journaled for rotation in a cover plate 2 and another late 3'fixed thereto but spaced therefrom y means of posts 4. For rotatin said shaft 1 an electric motor 5, is connected thereto and mounted on plate 2. The connections comprise a pinion 6, on the motor shaft, meshing with an idle gear 7, which meshes with a pinion 8 on a shaft 9 carrying a worm 10. The latter meshes with a worm wheel 11 on the shaft 1. The shaft 1 is provided adjacent one end with a disk 13 secured thereto by means of a through-pin passing through said shaft and through the hub of said disk. A disk 14 of insulation is rotatably mounted on said disk 13 and frictionally held thereagainst by means of a plurality of springs 15 loosely and adjustably mounted on the lower end of shaft 1 by suitable means, such as nuts 16. The disk 14 carries, on one surface thereof, a pivoted switch arm 17 biased in the direction of the arrow (see Fig. 4) by means of a spring 38. This switch arm 17 is adapted to engage one or the other of lugs 18, 19 located on disk 14 on opposite sides of said arm.

eans are provided for normally locking said disk 14 and its switch arm against rotation. This means may assume the form of a plurality of manually operable plungers or keys 20 slidably mounted in plates 2 and 3 and preferably equidistantly spaced on a circle with its center at the axis of shaft 1.

Eachkey is preferably provided with a compression spring 21 spaced between acollar 22 on the key and .the plate 3 and tending to urge the key to upward position. The arm 17 is of such length as to engage the lower end of any one of the keys 20 which happens to be in depressed position.

cans are provided whereby each of the keys when depressed is locked in depressed position and any previously actuated key is released on actuation of any other key. This .means is shown as a disk 23 provided with as many radial shoulder portions as there are keys 20. and loosely mounted on the shaft 1. The disk 23 is given a bias in the direction of the arrow in Fig. 4by means of a spring 25 surrounding the shaft 1 and secured at its op osite ends to the plate 3 and disk 23.

Each key is'provided with an undercut por- 45 with two extending conically shaped poi-- tions 27 and 28 as clearly shown in Fi 5.

Slip rings 29, 30 provided on the periphery tion forming a shoulder 26 and own (see Figs. 4 to 8) as comprising a of disk 14, together with brushes 31, 32 mounted on a block of insulating material 33 secured to one of the posts 4 are employed to lead current to the switch arm 17 and lug 19. The end of the shaft l'opposite disk 14 is provided with a disk 34 on which is placed a,

pointer 35 adapted to cooperate with a pointer 36 on plate 2 to enable the operator to determine the speed of shaft 1. Each of the keys 20 is preferably provided at its upper end with an indicating symbol 0, U, R, L, D, S, A, F (see Fig.6) and are also each provided with a symbol 37 painted or otherwise mounted on cover plate 2.

The shaft 1 is driven at a substantially constant speed and "to accomplish this function a speed responsive controller is employed. This controller is shown as a governor 40 the fly weights 42 of which are connected to the motor shaft 41. and to 'a sleeve 43 slidably mounted on said. shaft. The

sleeve 43 carries acontact 44 adapted to en-- gage a contact 45 adjustably secured to a block of insulation 46 in turn securedto cover plate 2.

The electrical connections ofthe above de-,

scribed automatic circuit controller will be described hereinafter. As previously stated a manually operable controller is also provided (see Fig. 7) and. comprises a key 47 slidablymounted in cover plate 2 and block 46 and adapted to move a spring contact 48 against its A light or other signal 54 mounted on cover.

plate 2 and visible-through a glass covered opening 55 in the latter completes the structure of the sending means.

The electrical connections and operations of the sending means may be understood by reference to Figs. 3, 4 and 6. The switch 17 19 is connected in series with the normally spring action into engagement with a contact 49. The key 47 is preferably K, is adapted to break closed. switch K by means of conductors 100 r and 1 01 and the switch I is shunted across these conductors. ,The motor 5 is shown as shunt connected to a battery 102. This motor is kept running at a constantpredetermined speed by means of a resistance 103 in series with the armature of the'motor and connected at its terminals to the governor contacts 44,

It will be seen that the'circuit between conductors 100 and 101 is normally open as the normal position of the switch '17, 19 is open, as indicated in Fig. 4,

with the key 0 depressed. Now let us suppose that the shaft 1 is making a complete revolution in one second and that the key U is depressed. The key 0 is released, the disk 14 is rotated in the direction of the arrows in Figs. 3 and 4 and after a slight interval of time, the arm 17 contacts with lug 19. Contacts 17, 19 remain closed until the outer end of arm 17 engages; the lower end of key U when the arm 17' is, disengaged from contact 19 and engaged with lug 18 thus opening the cir cuit between conductors 100 and 101 and stopping rotation of the disk. Thus by the above operation, the circuit 100, 101 is closed for slightly less than one-eighth of a second. If key R had been depressed instead of key U the circuit would have been closed for slightly less than two-eighths of a second etc. The circuitmay also be closed between conductors 100, 101 by operating key I and keys 0, U, R, S, D, L, A, F may be operated without efiecting the circuit by first operating key K and holding the latter depressed.

A relay 104 is connected in series with battery 102, across conductors 100, 101. The indicating light 54' is connected in shunt with relay 104 and indicates when the sending means is o erated.

The specific etails of the wireless system employed form no part of the present invention, and for this reason, for the purpose of illustration, a conventional set well recognized in the art is illustrated. The wireless transmission is shown as comprising a sending set 56 and a receiving or detecting set 57 (see Figs. 3 and 24).

The selective means comprises a switch arm controlled by the 'electro-magnets 58 and automatically positioned with respect to a plurality of contacts in accordance to the impulse received by the receiving means.

The selective means isshown in Figs. 9

to 12 and 24. The; syvitch armis inthe form of a resilient arm 60 mounted on the outer end of a shaft 63 suitably journaled in plates 62, 65. The. last mentioned plates, of which the one 62 is preferably made of insulating material, are mounted in juxtaposition with respect to.each other but in spaced relation with respect to a plate 67 by means of posts 66. The plate 67 may be secured to the frame of the electric motoror other power means 68 which may be in all respects similar to motor 5. The shaft 63 has secured thereto at its inner end a ratchet disk- 64, said shaft terminating with said disk-'.- The last mentioned disk may be frictionally driven by a gear wheel 69 secured to a shaft 70 journaled in plate 67. The shafts 63. and 70 although in alignment are not connected to each other'except through the gear 69, disk 64 and a friction disk 82 mounted between the latter. A spring 71, adjustably connected at the outer ends to two of the posts 66 and engaging at its central portion, the shaft 63, is employed to adjust the frictional torque between the gear .69 and disk 64. A train of gears, 73, 72, 74, 75, is employed to drive the gear 69 fromthe shaft of motor 68 and for the purpose of maintaining the speed of the motor 68 substantially constant a governor 76 similarto the governor 40 is employed. The governor'shaft is rotatably mounted in a bracket 77 secured to the frame of, motor 68 and a pinion 78 mounted on the governor shaft and meshing with gear 72 is employed to drive the governor. An adjustable contact 79 mounted on, but insulated from bracket 77 and cooperating with the contact 80 on a sleeve sliding on the governor shaft, is employed to control the motor connections.

In order to control the position of ratchet disk 64, and consequently arm 60, from the electromagnet 58, a centrally pivoted pawl T-shaped comprising arms 83, 84, 85, rigv idly connected to each other and pivoted at their junction to the plates 67and 65. A spring 86 (Fig. 9) is employed to bias the arm in a ratchefl'engaging position and the arm :84 isprovided with an armature 87 adapted'to be attracted by the magnets 58 mounted below said armature by means of a bracket 88 secured to twoof posts 66.

In order to lock the arm 60 against operation by interference, means controlled by electromagnets 58 are provided for locking the disk 64 against operation when an impulse of more than a predetermined length is impressed on said electromagnets. The

angular movement ofthe lever 81 on energization of electromagnets 58 (see Fig. 10)

is. restricted by means of a segmental gear for a sufficient length of time the segment 89 will be moved downwardly until it passes under shaft 63, when arm 85 will be permitted to move the lug 90 into the path of pin 91. to arm 85 and at the other to segment 89 is employed to return the latter to upper position, which movement is limited by a stop 93 mounted on the plate 65.

A plurality of electrical'contacts 61 are mounted on plate 62 in a position to .be en- .gaged by arm 60 in its various positions for the purpose of controlling a plurality of translating devices.

The electrical means are indicated in Fig. 24. For convenience in explanation the circular row of contacts 61 nearestthe center are termed m- A spring 92 connected at one end connections of the selective tact 106 is fixed and contact 107 carried by armature 87 Inner contacts U, R, A, S, F, D, and L are each shown as connected to relaysU, R, A, S, F, D, and L respectively of which the other terminals are connected to the line wire 105'. I

The motor 68 is connected and controlled in the same manner as motor 5, so as to rotate the shaft 70 at the same speed as shaft 1, i. e.,'

one revolution per second. If magnets 58 are energized for a length of time slightly less than one-eighth of a second the pawl 83 will release the disk 64 and permit the arm to rotate through one-eighth of a revolution. If the magnets 58 are energized longer than oneeighth of a second, but less than two-eighths of a second, the arm will rotate through twoeighths of a revolution, etc.

The circuits to the relays U, D, etc., cannot be closed while the arm 60 is wiping over contacts 61 as it is open at 106, 107 at this time. I The front contacts of relay 104 of the sending means are connected to the wireless sending set 56 and the front contacts of thesensitive relay 110 of the wireless receiving set 57 are connected in a series with magnets 58 across line wires 105, 105.

With these preferred connections and the shafts 1 and revolving at the same speed and the arms 17 and 60 in the position 9, suppose that it is desired to energize the relay U connected to inside contact 61 at the position U, all that is necessary is to depress the key U at the sendin station. Any of the other relays R, A, F may be selected in a similar manner. Although it is preferable to accomplish the selection by employing the automatic sending switch, it is obvious that the key I may be-employed for the same purpose if carefully operated with reference to time. v

If the switch arm 60 is at position 0 and it is desired to lock the selector switch against interference, it is only necessary to press key I for a time greater than seven-eighths of a second (under the conditions of speed assumed) which will cause the sector 89 to pass under pinion 63 to cause the lug 91 to engage lug 90. The position of the sponding to this position of lugs 91 and 90 is at I (Fig. 24) so that none of the relays R. A etc., are energized nor can they be'until magnets 58 areagain deener ed. Obviously if an interfering group of impulses is sent out by some one other than the operator at the sending station the magnets 58 will cause l and certain deenergized when steadily,

arm 6O corre- .low key v and lamp'121 will flash. If any other answer for example, two lights the arm 60 to be locked at I as atleast one of I these impulses will be longer than those contemplated in the present apparatus.

In order to inform the operator at the send ing station whether or not the selector switch at the receiving station is responding properly and also the condition of the apparatus at the receiving station answer back signals in .the form of a pair of lamps 120, 121 controlled by a flasher of contacts 61 are provided.

The flasher is shown in Figs. 9,10 and '12.

The shaft 70 carries a cam 111 adapted to engage and operate movable contact arms 112 and 113 which are biased to a position in engagement with the relatively fixed contacts in its rotation to break engagement between contacts 112 and 115 and contacts 113 and 114: and at a later interval make contact between 112 and a fixed contact 116 and between 113 and a fixed contact 116.. The contacts 112 to 116 are insulated from each other and from the plate 67 whichcarries them by means of insulation 117. The lamp 120, Fig. 24, has one terminal electrically connected to contact 113 and the following of the contacts 61: outer contact S, outer contact R and outer contact 0. One terminal of the lam 121 is connected to contact 112 and the fo lowing of contacts 61 outer contact L and inner conis split, middle contact R and outer. contact U; the contact 114 is connected to middle contact D,-middle contact L, inner contact I, the outer half of the split contact in row A and the inner half of split contact-in row F; apltact 116 is connected to middle contact I n outer contact A; and contact 116' is con nected to outer contact F. As the arm 60 is tacts 61 I provide a outer contact I around switch 106, 107.

By tracing the above described circuits it will be found that when the arm 60 stops on row 0 of contacts 61 both lamps 120, 121 glow on row U lamp-120 is out and 121 flashing or flickering, on row A both lamps flash together, flashes alone and goes 0' glows steadily and 121 is out and so on, as indicated by the corresponding indicia 37 on plate 2 (see Fig. 6). H

to inform him at any time of 115 and 114 respectively. The cam is adapted connected to outer contact it stops on row I of con-- shunt connection 122 from thengo! out, then lamp 121 ut etc., on row S 120 If the operator depresses one of the keys,

say key R, and the-arm 60 at the receivin station takes position R an answer ibackslgnal will be given corresponding to indicia'37 be- R, i. e., lamp will glow steadily back signal is given,

, interference by operating the sending keys in or by. holding down key K and then depressing the key corresponding to the answer back signal previously received. In the first case, both the arm 60 and arn1 17 will be restored to position 0. The operator may check up the speed of the shaft 1 at any time by the revolution of pointer 35 (seeFig. 6) and may adjust the speed if necessary by adjusting the contact 45 of governor 40. i

The selective instrument at the receiving station (Fig. 24) may also be locked against ways other than those above described. Thus assuming that one of the keys is depressed and it is desired to lock the receiving station against interference, one of the other keys 20 may be depressed to such an extent as to release the first mentioned key but not sufficiently to allow the disk 23 to engage the shoulder 26 (see Fig. 5) of the last mentioned key to lock the latter in depressed position. The switch 1719 then remains closed as there is no key 20 depressed to open it, so that a sustained impulse is transmitted thus causing the magnets 58 to lock the selective means. Obviously the above procedure may be adopted instead of utilizing the key I when it is desired to synchronize as previously outlined.

Instead of effecting the release of all of the keys 20 in the manner above'described, the

, same result may be accomplished by pushing a rod 400 (see Figs. 4 and 5) inwardly. This rod is shownas passing through an opening 403 in plate 23 and being turned over at 402. The button 401 at the outer end of rod 400 may be detachably secured to the latter by means of screw threads, so as to facilitate the I removal of the plate 2 for the purposes of inspection. 1

While my invention is applicable to various types of aircraft I have shown it applied to only one type i. e. a tractor aeroplane 201 (see Fig. 1) comprising the usual propeller 202, which is driven by an engine (not shown); rudder 203, elevators 204, ailerons 205, and main planes 206. While the usual chassis might be employed I prefer to use instead a launching truck 207 adapted to run on rails 208 and on which the device 201 is lead 211 in electrical contact with the engine or any other metallic parts of the aircraft as indicated diagrammatically in Fig. 24.

The answer back signals 120, 121 may be located at anyconvenient point on the aircraft as for example one on each of the opposite tips of. the upper plane 206 andthe line wires 105, 105 which supply energy to these lamps, as well as the selective means, may be supplied with direct current from any suitable source such as a wind-driven generator 212 carried by one of the struts of the aircraft. For a purpose which will hereinafter appear I prefer to use a generator 212 capable of delivering both direct current and three-phase alternating current.

In order to operate successfully the aircraft should be self-stabilizing. Various types-of stabilizing systems which have been invented might be used in the present combination. I prefer, however, to employ the one shown in Figs. 13, 14; 16 and 24 which comprises a gyroscopically stabilized pendulum 213 adapted to control a plurality of servo-motors in turn connected to certain of the controlling planes of the aircraft. The stabilized pendulum 213 is shown as comprising a gyroscopic rotor 214 rotatably mounted about its vertical axis in a frame 215 which in turn is pivoted in a ring 217 by means of pivots 216. The ring 217 is pivoted,

.by means of pivots 218, in brackets 219, secured to a base 220 which in turn is mounted on the aircraft in such a position that the arrow shown in Fig. 13 points in a fore and aft or longitudinal direction. As the pendulum will assume a position substantially fixed in space the relative movement between it and the aircraft may be utilized to effect the self-stabilizing function. Thus the ring 217 which is gyroscopically stabilized about the longitudinal axis may be utilized to stabilize a contact or plurality of contacts 224, 225,- 226 secured to said ring and'adapted to co-- the pendulum the position of the latter may be utilized to control the self-stabilization of the aircraft about its transverse axis. The

bail 227 may be pivotally mounted about the transverse axis of the aircraft in brackets 228, secured. to base 220, and may be provided with a groove 229 in which a roller 230, se-

cured to the lowerend ofthe pendulum, is

adapted to travel. The bail 227 is arc-shaped as shown so that the relative movement of the pendulum and .its support about thelongitudinal axis is not interfered with. The bail may carry contacts 224,'225', :226, in all respects similar to contacts 224, 225, and

226 and adapted to cooperate with brushes 221', 222, similar to brushes 221, 222 and carried by one of brackets 228. The contacts designated by the primed numerals may be utilized to control the elevators 204 as will later appear.

The position of the ailerons 205' may be controlled by gyro contacts 221 etc. through a servo-motor 231. This motor may assume the form .of a shunt wound reversible electric motor (see Fig. 24) mounted on base 220 and connected to the aileron actuating cable or .cord 251 through a drum 232. The latter may be secured to a shaft 233 (Figs. 13 and 17) rotatably mounted in a frame 234 secured to the base 220 and said shaft 233 may be connected to the motor pini'on 236 through a suitable trainof gears includin gear 235 secured to said shaft (see Fig. 17).

The servo-motor 231 may be controlled by its contacts through any suitable connections. The connections shown in Fig. 24 have been found to be advantageous. The shunt field of motor 231 is connected across the line wires 105, 105' and the armature is connected across brushes 221, 222. The contacts 224 and-226 are connected together and to one side of line 105, 105' and contact 225 is connected to the opposite side of said line. It will be seen that with the-parts in normal position, as indicated in Figs. 13 and 24, the armature of motor 231 is short-circuited and the latter is therefore stationary. Tilting of the air.- craft about the longitudinal axis, however, will cause one or the other of brushes 221,222 to disengage the contact 225 and engage-a corresponding one of contacts 224, 226 so that the motor 213' will operate the ailerons 205 in such a direction as to cause the aircraft to return to horizontal position.

I prefer to provide a follow-up connection between the contacts or brushes 221 etc. and the ailerons. This follow-up connection may assume the form illustrated in Figs. 13, 14, 16 and 17 and may be constructed substan tially as follows: The shaft 233 has secured thereto, at the end opposite the drum 232, a pinion 237 adapted to mesh with the teeth on a segiiiental rack 238 secured to shaft 239. The latter is journaled in the frame 234 and has secured thereto an upstanding arm 240 adapted to actuate a rod 243 by means of the rod 241 and bell crank 242. Thebrushes 221, 222 are shown mounted on an arm 244 pivotally mounted about the axis of the ring 217 and while the rod 243 might be directly connected to the arm 244 I refer to effect this connection through a-difigrential so that the brushes 221, 222 may be given a movement independent of that due to the follow-up rod 243, for a purpose which will hereinafter appear. This difi'erential connection may assume the form illustrated in Figs. 13 and 16. The arm 244 is provided with a segmental rack 246; andan arm 245, similar to eases? arm 244 and loosely pivoted about the same axis as the arm 244 is also provided with a segmental rack 247 racks 246, 247 are engaged respectively by intermeshing inions 248, 249 carried by an arm 250 loose y pivoted about the same axis as arms 244 and 245. The follow-up rod may be connected to either of the arms 245 or 250 and is shown connected to the former;

The utility of the remaining arm 250 will be apparent as the explanation is proceeded with- The brushes 221', 222' may control the sta- Y bility of the aircraft about the horizontal axis at right angles to the line of flight by means of elements identical to the elements between the contacts 221, 222 and the cable I -form o a gyroscope which I will hereinafter refer to as the azimuth o. I A

Calling attention to Figs. 13 and 15 it will be seen that I provide a gyro, designated generally as 252, and having its spinning axis normally at .253, 254. This gyro is shown mounted for precession about a horizontal axis at right angles to its spinning axis in a frame 255 which in turn is mounted for relative rotation with respect to the base 220. The frame 255 is j-ournaled at its lower end in a pedestal 258 secured to base 220, and terminates at its upper end in a shaft 256 journaled in a yoke 257 also secured to said base 220. The position of the gyro 252 being fixed in azimuth, the relative movement between the same and the aircraft may be utilized to. control the course of the latter. trol may I prefer electrical control I illustrate only this form (see Figs. 13, 15 and 24) Thus the shaft 256 may have secured thereto a contact or trolley 261 adapted to cooperate with contacts 262, 263 rigidly carried by a member 264 mounted on but not rotat- (see Fig. 16). The.

This conbe effected by various means but as able with the shaft 256. Slip rings 259 may be provided on shaft 256 and corresponding brushes 260 mounted. on yoke 257 for the purpose of conducting current not only to contacts 261', 262, and 263, but to the'three phase rotor of gyro 252. j The contacts last mentioned may be utilized to control directly, orindirectly through relays which I have illustrated .in Fig. 24, a suitable'servomotor connected to the rudder 203. i

The servo-motor 265 may assume the same form as servo motors 231 and 231' and may be connected to the rudder-operating cable 267 through a drum 266 a 'nd gearing similar 30 the connections of the last mentioned ;ervo=motors. A preferred form of electrizal connections between the contasts 261, 262, 263 and servo-motor 265 is shown in Fig. 24. The shunt field of motor 265 is connected across line 105, 105 and the armature is connected across the armatures of relays 268, 269. The front contacts of the latter, are connected together and to one side of line 105, 105 while the back contacts, which are also connected together, are connected to the opposite side of said line. The relays 268, 269 are connected together at one end and to one side of the line, as 105 and the other end of each relay is connected to a corresponding one of contacts 262, 263 and the contact or trolley 261 is connected to line wire 105.

The operation of the last described portion of my invention is as follows: The normal position of the contacts 262, 263 and 261 is shown in Fig. 24. Remembering the contact 261 is fixed in azimuth it will be seen that any movement of the aircraft in azimuth will cause one or the other contacts 262, 2 363 ,to

engage trolley 261 to energize'the servomotor 265 in the proper direction to cause operation of the rudder 203 to bring the aircraft back on its course. I prefer to provide a follow-up connection betweenthe rudder 203 and the contacts 262, 263 and as I wish to give the contacts a movement independent of that due to the follow-up connection, for

a purpose which will appear hereinafter, con

nections as illustrated in Figs. 13 and are employed.

A segmental lever 270 is shown connected to the servo-motor 265 in the same manner that lever 238 (see Fig. 17) is connected to its servo-motor. The upper end of lever 270 is connected by means of a link 271 to the upper end of the arm 272 of a rocker arm lever 273 journaled in one side of yoke 257. The other arm 27 4 of this rocker arm lever straddles a pin 275 which passes through a rod 27 7 slidably mounted in brackets 278 secured to said yoke 257. The member 264 is shown in the form of a worm wheel adapted to be enga ed by a worm 280 slidably but non-rotata 1y mounted on a shaft 281 journaled in brackets 278. Therod 277 has fixed thereto a pair of arms 279 one on each side of the worm and adapted to slide thelatter 011 its shaft on movement of said rod 277. Obviously movement of lever 270 will shift the contacts 262,

The mechanism above described and illustrated in Fig. 13, besides accomplishing the function of stabilizing the aircraft and holding it on a predetermined course may be utilized and form apart of means for steering the aircraft both in azimuth and elevation. Thus if arm 250' is moved in either' direc- -tion the contacts or brushes 221, 222 will be shifted to cause the aircraft to rise or dive at an angle correspondingto the direction and extent of deflection of said brushes from normal position. Likewise if the shaft 281 is turned the contacts 262, 263 will be shifted to cause the aircraft to turn in azimuth until the normal relationship between said contacts and contact or trolley 261 is reestablished.

Although it is not absolutely necessary I prefer to provide means for automatically banking my device when a turn in azimuth is made. This means may assume the form illustrated in Figs. 13 and 14in which the arm 250 is adapted to be moved by movement of an arm 282 fixed on shaft 286 of the azimuth gyro follow-up which shaft 286 has also secured thereto the lever 270. I prefer to make the connection between the arms 282 and 250 adjustable. Thus the link 283 may be adjustably connected, as indicated in Fig. 25, to the arm 282. The remaining end of said link 283 is connected through a bellcrank 284, pivoted on base 220, to a link which is in turn connected to arm 250. The connections are so made that operation of the servo-motor 265 to turn the rudder 203 will move contacts or brushes 221, 222 in such a direction as properly to bank the machine.

In order to control movement of arm 250 and shaft 281, and consequently the steering of the aircraft, from the selective system any suitable form of translating mechanism may be employed. Apreferred form of such mechanism, which I will term relay mechanism, is shown in Figs. 13 and to 23 and constructed substantially as follows The pairs ofrelays or electromagnets R, L, S, D, and U shown in Fig. 20 are shown as single electro-magnets in Fig. 24 to avoid unnecessary complication in the last mentioned figure. The entire relay mechanism is mounted on a base 290 mounted on, but above,

.base 220 by means of corner posts 291. The

base 290 carries a plurality of upright posts 292 which support at their upper ends a plate 293 which supports the depending electromagnets R, L, S, D and U. The posts292 support guide rods 295 on which a plurality of platforms 294,, 296 are slidably mounted. The platform294 carries a plurality of pawls 297 to 300 adapted tobe operated by electromagnets U, D, and S, S respectively and the platform 296 carries pawls 301, 302 adapted to be operated by magnets L and B. Each of the pawls is pivotally connected with its platform, as at 303 and. biased to inoperative position -by means of a spring 304:. Each pawl is provided with an armature 306 adapted to throw the pawl to operative position against the action of its spring 304 on energization of the corresponding electromagnets. Stops 305 may be adjustably mounted in the platforms to limit the throw of the pawls due to springs 30 1.."

A plurality, of independently rotatable shafts 307, 308 are rotatably mounted in posts 321, 322, has eccentrically slot connection between link 330 and arm 329.

292 andeach-have fixed thereto a plurality of ratchet wheels 309, 310, 311, 312, 313, 314 and 315 (see Fig. 23) adapted to be operated by corresponding pawls. The normal position of the parts and the number and re lationship of the teeth on the various ratchet wheels is indicated in the last mentioned figure.

Any suitable means may be employed for causing reciprocation of platforms 294, 296. The means preferred by me at this time is shown in Figs. 13 and 20 and comprises an electric motor 317 adapted to reciprocate said platforms constantly. The motor, which is mounted on base 290, rotates a shaft 320 by means of pinion 318 and gear 319 and a con? necting rod 325 is pivotally connected at one end to platform 296 and at its other end to a crank arm 324 on shaft 320. The shaft 323, which is driven by shaft 320 through gearing connected thereto at one end a connecting rod 326, which connecting rod is pivotally connected to platform 294.

The shaft 308 is connected through bevel gears 327, 328 to shaft 281 whereby, when platform 296 is reciprocating, energization of electromagnets R will cause pawl 302 to step its ratchet wheel 314 around to cause contacts 262, 263 ofthe azimuth gyro to be moved in such a direction as to cause the aircraft to turn to the right. The latter will continue to turn to the right as long as magnets R are energized. Energization of magnets L will cause turning of the aircraft to the left in a similar manner.

The shaft 307 carries, at one end, an arm 329 (see Fig. 22) connected to the arm 25.0 of the stabilizing gyro (see Fig. 13) by means of a link 330. For a purpose which will hereinafter appear I prefer to provide a pin and Thus the link 330 is provided with a pin 332 which passes through the slot 331, said pin being normally held at the bottom of the slot, against the action of spring 335, by the plunger of a normally de-energized electromagnet 333 carried by arm 329.

Calling attention to Figs. 13, 20, 22, 23, particularly the latter, let us assume that the platform 294 is being reciprocatedand that magnets D are energized. The pawl 298 is thrown into operative position to stop ratchet wheel 309 around an amount depending on the length of time the said magnets are energized, up to a certain limit. This causes the arm 250 and accordingly the brushes 221 222' to be shifted to cause the aircraft to descend at an angle depending on the length of time of energization of said magnets. Attention is called to the fact that the teeth on the wheel 309 are limited to such a number as to limit the extent of angular movement of shaft 307 and consequently contacts 221, 222' to suchan amount as to prevent the aircraft from being sent down at too sharp an angle under normal operating conditions. In order to restore the parts to normal position and thereby cause the aircraft to resume a course in a horizontal direction the magnets S are energized. Pawl 299 will then restore the shaft 307 to normal position (indicated in Fig. 23), the pawl 300 being inoperative at this time, for although it is thrown to down position the teeth of wheel' 311 are not in position to be engaged. In a similar manner the aircraft can be caused to ascend by energizing magnets U' and returned to straight-away by energizing magnets S. It will be noted the number of teeth on wheel 310 is limited so as to prevent the angle of ascent from exceeding the critical angle. By critical angle I mean that angle of inclination with respect to the horizontal which would cause the aircraft to stall or slide ba c The motor 317 may be shunt wound and permanently connected across line 105, as indicated in Fig. 24. The entire mechanism shown in Fig. 13'may' be mounted in any suitable position on the aircraft, as for example, within the casing 337 (see Fig. 1) Under certain conditions, trolling or sending station is located on another aircraft and the operator on the latter is forced .to abandon the manual control ofthe aerial torpedo 201, it is not desirable to cause the latter to drop immediately as it may not be over the target. I, therefore, prefer to provide a means, which may be started at any time in the flight of the air-' as when the concraft201 from the sending station and which will automatically cause the aircraft to descend sharply after any predetermined one of-a plurality of distances is traveled. F urthermore I prefer to provide means controlled from the sending station for selecting this distance while the aircraft 201 is in flight. One suitable form of apparatus is shown in Figs. 18, 19, and 24 and maybe constructed substantially as follows v The shaft 338 is driven by a propeller which might be the main propellerbut "is auxiliary windcarries a worm shown in the form of'an wheel 339. The shaft338 340 adapted to be engaged by a WOI'In Wl1GBl 341 revolubly mounted on a frame 342'pivoted at 343 to a base 344. The frame 342 may be biased to gear-disengaging position by means of a spring 345 and may be shifted to cause engagement of the worm and wheel ,341 by energlzation of the solenoid or elec- The worm-wheel 341 is tro-magnet A. shown as carrying. a switch arm 360 adapted to engage successively a plurality of contacts 361, 262, 363. The shaft 338 is also adapted to drive a switch arm 360 through speed-reducing gearing 349, 349 of which a part 349 1s carried on said shaft and a part 349 is carried by a bifurcated arm 350 and normally llt normally deenergized electro-magnet 356,

preferably connected in parallel with solenoid or relay A, is adapted when energized to attract and thereby release the catch 355 to allow a spring 357 to cause the parts of the gearing 349, 349' to mesh. The arm 360 is adapted to successively engage a plurality of. contacts 361', 362' and 363' carried by a disc 348 secured to arm 350.

The electrical connections and operation of the structure last described may best be understood by reference to Fig. 24 in connection with. the figures already referred to. By'pressing the key A at the sending station (see Fig. 3 and 6) the selective switch at thereceiving station will cause energization of magnets A and 356. Energization of magnet A will cause operation of switch arm 360 (Figs. 18 and 24) for a time depending on the length of time the said key A is in depressed position, so that any one of contacts 361, 362, or 363 maybe selected by the length of time key A is depressed.

top. of slot 331 so Energization of magnet 356 will cause the arm 360 to be slowly rotated and, if not stopped, to engage the contacts 361, 362, 363' after the aircraft'has travelled various distances, asfor example one mile, two miles or three miles. Assume that the operator at the sending station calculates that the device 201 is two miles from the target but he wishes to abandon control. He may then depress key A for a length of time to allow arm 360 to reach contact 362 when'the key A should be released. The arm 360 will now remain on the last mentioned contact and when the aircraft 201 has travelled two miles the arm 360' will engage contact 362' to close a circuit from line wire 105 through arm 360, contact 362 to contact 362', through arm 360 through relay- 364 (the function of which will appear hereinafter), through magnet 333 (see Figs. 20, 22 and 24) and magnets D to line wire 105.. The energization of magnet 333 will permit the spring 335 (Fig. 22) to raise the pivot 332 to the that the movement of link 330 due toenergization of magnets D will be eatly increased over the normal amount an aircraft will be sent down at a sharp angle. y

The aircraft 201 is adapted to carry a heavy charge of explosive material 365 (see Fig. 24) which I will term the main charge and while means mightbe provided for causing this main charge to explode on contact of the aircraft andthe target I prefer to explode this charge a predetermined distance above the ground. Furthermore, I prefer to provide a means for preventing premature accraft 201.

cidental explosion of the main charge before the aircraft 201 has left hometerritory.

Oneform of'exploding means'for the main charge is shown in Fig. 24 as a filament-366 adapted to glow when energized. This filament may be connected in series with the back contact of a relay 367, front contact of a relay 378 and a battery or other source of E. M.'F. 379. The relay 367 is normally energized through a fragile circuit breaker.

380 having a flexible conducting cable 381 of any desired length, normally wound on a reel or drum 382 rotatabl mounted on air-' This circuit reaker comprises a conta1ner of glass or other fraglle mater1al containing mercury or other conducting fluid which bridges exposed ends of conductors 383, 384 as long as the container is unbroken. Brushes 385 and slip rings 386 may be utilized to conduct the current to the conductors 383, 384. The magnet 378 is adapted to be energized only after the aircraft 201 has been launched and preferably only after the aircraft has traveled a distance sufficient to insure that it is over enemy territory. Thus said magnet 378 is connected in series withnormally open contacts 387 adapted to be closed by a pin 388 on an arm 390 frictionally carried by the shaft 421 to which a worm gear 389 is secured. The latter meshes with a worm+i20 on the shaft 338 (Fig. 18) so that the contacts 387 will not close ;until the aircraft has travelled a predetermined distance, which distance may be varied by adjusting the initial angular position of the pin 388 with respect to its contacts. The reel 382, prior to lunching is locked against turning with the cable 381 wound thereon, by means of a shoulder 422 thereon which is adapted to be engaged by the armature of electromagnet 37 8 when the latter is deenergized. The operation of the means above described is substantially as follows:

When the machine 201 is about to be launched the magnet 378 is deenergized so that the filament cannot be energized even though the'circuit breaker 380 should be broken accidentally. At this time the last mentioned device is in a position close to the body of the aircraft to avoid breakage; (See Fig. 1). When the aircraft has travelled asuflicient distance to reach the enemy territory the contacts 387 close to energize'magnet 378 to cause the latter to attract its armature. The last mentioned operation not onlyarms the machine (i. e. puts filament j circuit in a condition to be closed on breakage of breaker 380) but re-' in cocked 365. By designing the cable 381 of the de-' sired length the main charge may be made to explode at any reasonable distance above the ground. 4

Besides the main charge, above described, I prefer to provide an additional or auxiliary charge adapted to be dropped before or simultaneously with the main charge thus increasing the effectiveness. To avoid unnecessary complication of the present disclosure I have limited the number of auxiliary charges to one but it is obvious that as many of such charges may be employed as are dedesired. The auxiliary charge may assume (see Figs. '1 and 2) the form of a bomb 425 constructed substantially as follows:

The central portion of said bomb is adapted to contain a charge of explosive material 426 having a primer 427 adapted to be cngaged by a firing plunger 428 operable in a sleeve 430 in the tail portion of the bomb. The plunger 428, when cocked against the action of the spring 436, is adapted to beheld position by a pivoted catch 431 adapted to extend through an opening in the sleeve 430 and biased to plunger-engaging position by a spring 432. The catch 431 is adapted to be released by means of a cord or cable 433 connected thereto and to a slidable p-in 434 in the nose of the bomb. A cap 435 may be provided on the said nose to prevent operation or breakage of the pin 434 prior to the time of launching.

cans are preferably provlded for cock ing the bomb firing mechanism only after the bomb has left the aircraft. Thus the firing plunger stem 429 has connected thereto a wire or cable 437 which is connected at its other end to the body of the aircraft. This wire or cable is designed to have suflicient tensile strength to cook the plunger 428 against the action of its spring but insulficient strength to resist rupture after the plunger is cooked.

The bomb 425 is shown detachably connected to the aircraft by means constructed substantially as follows: A' plurality of uprights 439 corresponding number of depending brackets 438 on the aircraft 201.- The uprights and brackets are provided with complement-a1 apertures in which rods 440, 441 are adapted to seat. The latter are pivotally connected at their central ends and may be-prevented from outward end movement in said aperturesby means of plates 445 carried by the brackets 438. One of therods, 441 is shown as provided withian integral upwardly extending arm 442 provided with a shoulder adapted to be supported on a shoulder provided on armature 443 pivoted to the under portion of the body of the aircraft 201. Obviously when the electromagnet F mounted injuxtaposition to said armature is energized and attracts the latter, the central porsending station provided may be connected to are provided on the bomb and a tions of the rods 440, wardly, brackets The energization of the electromagnet F as previously described, is adapted to be controlled fnom the selector switch (see Fig. 24) which in turn is cont-rolled from the sending station. Thus the bomb 425 will be dropped by depressing the key F (see Fig. 6) at the the aircraft is over enemy territory.

In order to prevent premature accidental energization of the magnet F and the consequent dropping of the bomb 425 while the aircraft is still over home territory the front contacts of a: relay 440' may be inserted in the circuit of the magnet F (see Fig. 24) and the relay 440 magnet 378 in series with distance controlled contacts 387 previously described.

If the bomb 425 has not been dropped by depression o-f,the key F at the tionand it is desired to drop it after a predetermined distance has been travelled it is :only necessary to depress the key A at the may be shunted across sending staings as disclosed in my United States Letters Patent 1,186,856, patented June 13, 1916. The primaries 452, 453 of these induction motors the three-phase mains 454 which are connected to the A. C. side of the generator 212.

I have disclosed, also, the azimuth gyro 252 against turning in aziml th prior tothe time of launching of the aircraft. Calling attention toF i 13 and 15 it may be seen that asleeve 462 is lidably mounted in one side of yoke 257 and mally held, against the action of a spring 463, in a position in which it engages the stud 253, by means of a pin 461 on the armature of an electromagnet 460 carried by the same side of said yoke. energized it attracts its armature, withdraws pin 461, and permits the spring 463 to cause means for locking tive to the yoke 257. I prefer to connect the is nor- When the magnet 460 'is magnet 460 in such a manner that it will be automatically energized only after the azimuth gyro rotor has been spun up to substantially its operatin speed. Thus, as indicatedin Fig. 24, t e retarded relay,"shown symbolically at 500 and connected across the line 105,105 will not, on energization of line 105, close its front contacts to energize magnet 460 until the rotor of gyro 252 has substantially reached its operating speed.

The operation of my invention may be briefly summarized as follows: The aerial device or torpedo 201 is placed .on the truck 207 as indicated in Fi 1. The cap 435 is removed, the arm 60 of the selective means is placed in off position (0) and the key (0') is depressed at'the sending station (see Fig. 6).

The engine (not shown) is then started to 7 drive the propeller and the aerial torpedo is held against moving forward. The air current generated by the propeller will drive the generator 212 which will spin up the gyro rotors. As soon as the latter have substanially reached normal operating speed the 'retarded relay 500 will cause the release of the azimuth gyro locking means 462. Preferably, although it is not absolutely necessary, the wind-wheel 339 should be held against rotation until the device 201 is allowed to move forward. The key U is then depressed which will cause the elevators 204 to be set to cause the machine to rise and the device 201 is released. The latter then moves forward and rises leaving the launching truck. The

device 201 may now be sent straight ahead or to the right or left by operating the keys S, R or L at the sending station. After the aircraft has travelled a suflicient distance to carry it over the enemy territory the contacts 387 will be closed and the device armed. Closure of contacts 387 also causes the cable 381 to run out. If it is desired to drop the bomb 425 the key F at the sending station is depressed. If it is desired to drop the main explosive the aerial device is simply directed down at the target by depressing the key. D... If it is desired to abandon the distant control of device 201 the automatic mechanism may be thrown in by depressing the key A at the sending station and the distance at which the device 201 will be automatically dropped may be selected by the len th of time the key A is depressed. When this selected distance has been travelled the magnet 364, 333 and D will be energized.

Energization of magnet 3641wi1l cause energization of the magnet F to cause the bomb 425 to drop and energization of 333 and D will cause the main charge to dive at a sharp angle. The operator at the sending station will be constantly apprised of .the condition of the aerial device and whether it is respond ing properly by the answer-back signals. It

1s preferable when it is not desired to keep the selector arm on any of contacts 61 corresponding to positions U, R, A, S, F, D, L that the ke I at the sending station be depressed. T e last mentioned operation will prevent anycontrol by interfering signals.

My device is susceptible of various modifications.- For example the device'instead of being launched from the truck 207 may be provided with pontoons and launchedfrom the sea. Furthermore by omitting the main charge 426 the bomb 425 could be dropped on the enemy and the device 201 then brought back to the home station or base and rearmed.

It may be desirable, under certain condi-.

tions, to provide means for automatically maintaining the aircraft at a certain height. A barometric or other height responsive device may be employed for this purpose. Thus in Fig. 24a I have shown one form of barometric device, designated generally as 510.

This device is shown as comprising a par tially or totally exhausted air-tight contamer 511, closed at one side by means of a flexible diaphragm 512 which tends to move outwardly against the pressure of the atmosphere. A contact lever 513 pivoted at 514 is connected at one end, by means of a link 515 to the center of said diaphragm 512. The end of the lever 513 opposite said link 515 is adapted to cooperate with a pair of opposed,

resiliently mounted adjustable contacts 516,

soon as descent is started contact will moveover to 517 and bring the craft back to altitude again.

Thecontacts 513, 516, elevating rudder 2040f the aircraft by being connected to the magnets S and U and prefgradually erably the opening and closing of the circuit to the contacts should be controlled by the selector switch arm 60. In Fig. 2411 I have shown the outer contact 518 of row I of the selector switch as split by insulation, the upper half being connected to line wire 105 by means of conductor 122 etc. (in the same manner as the whole contact is connected in Fig. 24), the lower half being connected by means of a conductor 519 to the lever 513 of the barometric device 510. The contacts 516, 517

are connected by means of conductors 520,

521, to the magnets U and S respectively.

approached the contact moves 517 may control the l Furthermore as indicated in Fig. 24a means may be provided for causing the aircraft to drop its auxiliary charge and dive sharply downward when a predetermined distance from the starting position is reached, said means being called into action by a pro-.

longed impulse either from the sending station or an interfering station. This means may assume the form of a switch arm 522 preferably frictionally carried by a shaft 523.

rotated at a reduced speed by the shaft 338 (of the device shown in Fig. 18) through reduction gearing 524, 525. The switch arm 522 is adapted to engage a contact 526, carried by the disc 527 secured to bracket 528, after the aircraft has traveled a predetermined distance from its launching point.

The switch arm 522 may be connected to contact 518 by'means of a conductor 530 and the contact 526 may be connected to the arm 360" by means of a conductor 531.

Preferably and for purposes which will hereinafter appear a relay 532 is inserted in the connection between magnets 333 and D, the back contacts 533 of said relay being inserted in the conductor 519. I prefer also to insert an electro-magnet 534 in the connection between the magnet 356 and line wire 105', said electro-magnet 534 being adapted to attract a pivoted latch 535 normally in engagement with a pivoted arm 536 adapted to be pulled away from said latch by means of gravity or a spring 537. Obviously the latch 535 and arm 536 when once disengaged will remain so even though the magnet 534 is de-energized. Ihe latch 535 and arm 536 form a circuit-breaker inserted in conductor 531.

. My system, with the elements 510 to 537 added as indicated in Fig. 24a, may be operated substantially as follows: The aircraft may be prepared for launching as previously explained and in addition the contacts 516, 517 are adjusted to the predetermined low and high levels respectively and the switch 522, 526 to the range of the target. The key U (Fig. 6) being depressed and consequently the arm 60 on the row of contacts U the aircraft will start to rise and continue rising when released. However, instead of operating the key S to cause the aircraft to assame a level course whenever desired, the

last named function may be accomplished automatically by depressing the key I at the sending station thus causing the arm 60 to engage contact row I. If the last mentioned operation is performed the aircraft will continue to rise until the predetermined high level is reached when the contacts 513, 517 will close to energize magnets S to cause the aircraft to assume a level course as previously explained. If the arm 60 is kept on contacts I, either by the operator at the sending station or by an interfering signal, the barometric device will maintain the aircraft between the predetermined high and low levels. When there is no interference the .air craft may be steered from the sending station in the ordinary manner previously described except that the arm 60 is kept on position 0 instead of position I in the interval or intervals in which no control is being exercised, in which event the devices 510 and 522, 526 will be rendered inoperative due to the fact that the circuit is open between 122 and 518.

If an interfering signal or impulse holds the arm 60 on contacts I up to the time that the switch 522, 526 closes, the magnets 364, 333 and'I) will be energized to release the auxiliary charge and cause the aircraft to dive sharply as previously explained. It

.will be noticed that when magnets 364, 333

and D are energized, as above set forth, the relay 532 will also be energized to automatically cut out the barometric control. The operation resulting from depression of key A at the sending station is substantially the same as previously described except that by subsequently depressing the key I the baro metric device will be rendered operative to control the level of flight of the craft until the selected distance has been traveled when the relay 532 will render said device 510 inoperative. It will also be noticed that when the magnet 356 is energized, as a result of depression of the key. A at the sending station, the switch 535, 536 will be opened to break the circuit 531 and thus render the device 522, 526' inoperative. D

The additional mechanism shown in Fig. 24a may be placed in any convenient position on the aircraft as for example, in casing 450 (see Fig. 1). It will be understood that the mechanism and structure 518 to 531' shown in Fig. 24a may be added to that shown in Fig. 24 with but slight changes in the structure in the last mentioned figure.

Among other advantages it will be seen that as my device carries no human operator it will be extremely difficult to bring it down by gunfire as the vital control parts may be heavily armed.

In accordance with the provisions of the patent statutes,.I have herein described the principle of operation of my invention, together with the apparatus, which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others-omitted without interfering with the more general results outlined, and the invention extends to such use.

Having described my invention, what I desire to secure by Letters Patent is:

1. In combination, an aircraft, means for changing the direction of said aircraft after it has traveleda predetermined distance, and means controllable from a distance for starting the operation of said first named means while the aircraft is in flight.

' 2. In combination, an aircraft, means for steering said aircraft, means for controlling said steering means from a distance, normal- 1y inoperatlve means for changing the di- 

